A Fast and Easy Nitroblue Tetrazolium Method for Carrier Screening and Prenatal Detection of Chronic Granulomatous Disease

Background: Analysis of the functional activity of neutrophils is of great importance in the differential diagnosis of patients with recurrent bacterial infections. It has long been established that stimulated polymorphonuclear leukocytes reduce nitroblue tetrazolium. Application of a simple and reliable nitroblue tetrazolium method that clearly differentiates the chronic granulomatous disease patients and heterozygote carriers in some groups suspected to have chronic granulomatous disease was investigated. Methods: This study consisted of 197 samples taken from 100 children (2 – 24-month-old) and 81 neonates (aged <2 months) referred to our center either due to a suspected bacterial infection or suspected immunodeficiency. The sample also included 16 cord blood samples. Fifty healthy adult individuals were enrolled in this study and were diagnosed as normal control. Neutrophil reduction of nitroblue tetrazolium can be stimulated in vitro by protein kinase agonists such as phorbol myristate acetate, resulting in release of superoxide anion. Results: Phorbol myristate acetate is an exceptionally powerful stimulant and when used in conjunction with glass adherence, caused nearly all normal neutrophils to become transformed and reduced nitroblue tetrazolium to formazan deposits. Of 197 blood samples, 9 were diagnosed as having unrelated chronic granulomatous disease and 7 were carriers of X-linked or autosomal recessive chronic granulomatous disease. The carriers had a range of 15 – 75% stimulated neutrophils. Conclusion: We have established a phorbol myristate acetate-stimulated nitroblue tetrazolium test for detection of chronic granulomatous disease patients, which clearly differentiates the chronic granulomatous disease patients from heterozygote carriers. The results in cord fetal blood indicate that this test may be used for antenatal diagnosis of affected boys, carrier females, and autosomal recessive variants of chronic granulomatous disease. The technique is simple, fast, inexpensive, and requires only a few microliters of blood.